BRUSSELS. Nov 23 (Interfax) - Significant progress has been made in the investigation into the murder of Novaya Gazeta journalist Anna Politkovskaya, Russian presidential aide Viktor Ivanov said.

"As regards Politkovskaya's murder, as far as I am informed, the matter has advanced quite far," Ivanov said at EU-Russia negotiations in Brussels on Friday. "There is confidence that this crime will be solved," he said.

The theories pursued by the investigators have proven fruitful, Ivanov said. "The investigation will certainly be brought to a conclusion," he said.

"As far as I know, three people have been arrested under this case, and their custody terms were extended just recently to continue the investigation," Ivanov said.

"We understand that journalists are a sensitive link, but we see that similar crimes are committed in other countries as well," he said.

The government is responsible for the security of all of its citizens, wherever they work, including journalists, he said.